Oil prices stabilized on Friday as the US geared up for the start of its summer driving season, when demand for gasoline hits an annual peak in the world's biggest energy-consuming nation.
New York's main contract, light sweet crude for delivery in July, crept up US$0.05 to close at US$71.37 a barrel. But in London, Brent North Sea crude for July delivery eased US$0.12 to settle at US$70.59 a barrel.
Both markets closed early on Friday ahead of a long weekend on both sides of the Atlantic. In the US, tomorrow is Memorial Day, the traditional start of the summer vacation season.
Despite the markets' quieter tone at the end of a volatile week, BMO Nesbitt Burns analyst Bart Melek said investors should brace for more choppy trade in the week ahead.
"We continue to see considerable upside risk for oil as the hurricane season starts and more aggressive action is taken to curtail Iran's nuclear ambitions," he said.
"Gasoline also rose for the third day this week on Thursday ahead of the start of the peak US driving season, which stretches from the Memorial Day weekend to Labor Day [on Sept. 4]," Melek said.
A key focus for the markets next week will be a meeting Thursday in Venezuela of oil ministers from the 11 members of OPEC.
Analysts expect the OPEC countries, for now, to maintain their total production quota of 28 million barrels a day.
"As long as prices are hanging above US$70 a barrel, the likelihood of a production cut by OPEC is virtually zero," Alaron Trading energy analyst Phil Flynn said.
"But I do think that a lot of the OPEC producers are going to be concerned about the talk of slowing [world] demand. So it wouldn't surprise me if they drop hints of a possible cut somewhere down the road," he said.
This past week, crude futures had rebounded above US$70 on Thursday, after US economic growth data was revised up and because of the simmering diplomatic crisis over Iran's nuclear ambitions.
That rally came after both the New York and London contracts had shed nearly US$2 on Wednesday on US government figures that showed robust supplies of gasoline heading into the summer driving season.
"The Iranian issue, even though it is off the front pages, remains there and will provide support to high prices," said Victor Shum, an analyst with energy consultancy Purvin and Gertz in Singapore.
"It will set somewhat of a high floor [for prices]," he said.
The fear is that Iran could halt exports should the UN impose sanctions on the Islamic republic.
Iran insists its nuclear programme is strictly for civilian energy production but the West suspects Tehran is planning to build nuclear weapons.
Forecasts of a potentially busy Atlantic hurricane season will also keep prices firm, dealers said.
Last year, hurricanes Katrina and Rita devastated oil refineries and rigs along the US Gulf Coast, sending oil prices to then-record highs.
This year's hurricane season -- starting in June and ending in November -- will be "very active" but less severe than last year, according to a report issued this week by the Miami-based National Hurricane Center.